Fuel-injection valve for diesel engines



my 27,193@ D. E. SELBY -M FUEL INJECTION `VALVE FOR DIESELVENGINES l I Filed May 21, 192@ 2 Sheets-Sheet l MGEEEE l 2 Sheets-Shines?, 2

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SELEY FUEL INJECTION VALVE FOR DIESEL ENGINES Filed'iviay 21a 1928 Patented May 27, 1930 `IWIG'IB'I.' E. SELBY, OF BALBOA, CALIFORNIA FUEL-INIT ECTION VALVE FOR DIESEL ENGINES Application led May 21,1928. Serial No, 279,234.

This invention relates to apparatus for feeding fuel into the combustion chamber of'that type of internal combustion engine operating upon the Diesel cycle, or according to the isobaric expansion principle'. This type of engine employs for fuel, any one of a number of oils of relatively high coefficient of viscosity; and accordiugly, one of the in. herent diiculties encountered is in thoroughly comminuting the viscous oil, mixing it with air, and lvaporizing it, especially at the high compression pressure required for` the` successful operation of this type of prime mover. The successful design of any heavy oil engine necessitates eiiicient mixing of the fuel 'with air, and thorough vaporization of the resultant mixture. This is acc mplished A with relative ease when the fuel i injected into the combustion chamber with a quantity of air at relatively high pressure. This is called the air-injection type of fuel injection.

However, the problem is not so simple when the airless-injection or solid fuel injection design is employed. One manner of gaining the desired comminutionof the liq` uid fuel upon its injection into the combustion chamber, is by imparting to t-he fuel oil, sucha high pressure that when the injection 30 valve is opened, the fuel is sprayed into the r cylinder at a high velocity, resulting in its being thoroughly broken up into a fine spray. j This is difficult to accomplish however, since the injection of fuel must occur at the time of highest compression within the cylinder; audit can therefore readily be appreciated that the injection valve must be able to with! stand .enormously high pressures as well as the extremely high temperatures to which the 40 cylinder heads of this type ofengine are subjected. l

Frequently, air-injection fuel lvalves arev constructed without any mechanical connection to the moving parts of the engine for opening the valves, the opening of the valves being effected by increasing the pressure of the fuel itself behind the valve until the valve is forced open against the action of its closing spring and against the compression pressure within the cylinder. In this type of installation, a fuel injection is timed by means j of the fuel `pump itself. Owing to the high temperatures at the cylinder head however, the pump must be at some distance from the valve, necessitating the employment of a relatively long fuel line to establish communication therebetween; and vas a result, the'inertia of a column of liquid of considerable length, must be overcome each time' the fuel is injected. This gives rise to inac curacy in the timing of the injection, since the' fuel at the pump will start to move before the fuel adjacent the'valve.' Liquids of this class are ordinarily conceived as being uncompressible; but with the extremely high pressures involved, the amount of compression of thecolumn of liquid is sullicient to cause such inaccuracy.

This system also requires the employment of an intricate and delicate pumping mechanism capable of nice adjustment as to time of operation, and consequently, relatively delicate and subject to break-down.

It is an object of my invention therefore, to provide -an airless-injecton valve operable by means ofa suitable mechanical connection to certain of the moving parts of the engine, to open the valve at the desired time -during the cycle of the associated cylinder. Another object is theprovision of a mechanically operative valve' capable of withstanding very high pressures so that the oil can be supplied thereto at maximum pressure,

either continuously or prior to the time of opening of the valve, and wherein the period of injection is determined by the length of time that the valve is open, in contradistincftion to the system wherein the period of injection is determined by the stroke of the f-uel pump.

Another object is the provision of means for adjusting the clearance of the needle valve from its seat so as to regulate the quantity of fuel injected without having to change the valve operating mechanism. Another object is the provision of a valve of the general character described, having resilient means interposed between the needle valve and the operating means so that the stroke of the needle valve can be regulated without E Lacasse changing the stroke of the operating mechanism.

The invention possesses other objects and features of advantage, sonic of which, lwith the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated'in the drawings 5 5 of Fig. 3.

horizontal sectional View, the

accompanying and forming part of the specification. It is to be understood that l do not limit myself to the showing made by the said drawings and description, as l may adopt variations of the preferred forni within the scope of my invention as s et forth in the claims.

' Referring to -the drawings:

Figure l is a vertical sectional view taken through the cylinder head and upper portion of the cylinder of a Dieselengine, and showing'my improved injection valve in elevation thereupon.

Fig. 2 is a top plan view of the structure disclosed in,-Fig. 1. l

Fig. 3 is an enlarged, vertical sectional view of the inject-ion valve, the operative parts thereof being shown in the position assumed thereby when the oil passageway is closed.

Fig. 4 is a view similar to Fig. 3, with the operative parts shown in the position assumed thereby while fuel is being injected through the valve.

'.Fig. 5 is a horizontal sectional view, the plane of section being taken upon the line Fig. 6 is a plane of section being taken upon the line 6-6 of Fig. 3.

Fig. 7 is a horizontal sectional view, the lane of section being taken upon the line 7'7 of Fig. 3.

Broadly considered, the fuel injection valve of the present invention comprises a housing adapted to be secured in position upon the cylinder head preferably of a Diesel engine with the inner end thereof extending through the head into the associated combustion lchamber. A valve seat is provided within the housing and a needlel valve associated therewith to -control the flow of fuel through the Resilient means are interinjection valve. posed between a portion of the housing and the needle valve for urging the needle valve onto its seat, and adjustable nieansare provided for limiting the movement of the needle valve away;I from the scat to 'control the amount of fuel injected.

Means are also provided for lifting the needle valve away from its seat against the action of the said resilient means, and further resilient means are interposed between the lifting means and the needle valve so that the adjustable means may be brought, into engagement with the needle valve to limit its stroke without altering the stroke of the lifting means. j t

The specific embodiment of the invention herein disclosed isl shown in operative position upon the cylinder head 6,which closes the upper end of aA cylinder 7 of a Diesel engine, within which a piston 8 is reciprocable, and' which is provided with suitable cooling vmeans such as the conventional water jacket 9. 'llhe cylinder head 6 is similarly water-jacketed as at 11, and has the conventional valves such as the air inlet valve 12 and exhaust valve 13, since the engine with 'which my improved needle valve-is shown is of the foui`-stroke cycle type.

rThe injection valve which is indicated in its entirety at 16, comprises an elongated housing which is made up of a body portion 17 and a sleeve 18 threaded onto the upper end thereof. The body portion 17 is preferably cylindrical and of such length that it extends completely through a suitable recess 19 in the cylinder head 6, so that its inner end 2l reaches into the coinb-ustion Chamber 22 of the associated cylinder 7.

A suitable flange 23 is provided adjacent the' upper end ofthe body portion 17 through which holding-down bolts 24 may be passed and threaded into the top of the cylinder head 6 to lrigidly retain the injection valve 16 in position. A bore 26 extends preferably axially through the body portion 17; and a lateral Abore 27 extends from the bore 26 preferably through the flange 23, .and is provided at its outer end with suitable threads 28 by means of which the fuel line 29 may be attached.

rlhe lower 4end 21 of the body portion 17 is threaded as at 31, for the reception of a ferrule 32 by means of which a suitable valve seat and atomizing nozzle 33 may be securely held in position. The nozz'le 33 is provided with a central bore 34 adapted to be brought into register with the bore 26 of the body 17 when in position upon the lower end of the body 17, terminating in a preferably tapered seat 36. lt is to be observed that the seat 36 is closely adjacent the atomizing apertures 37, for by this construction it is made possible to obviate the drip of fuel which occurs when employing injection valves wherein the valve seat is at some distance from the atomizing apertures.

A needle valve 38, slightly smaller than the bore 26, is reciprocable therein with its lower end 39 tapered complementarily to the tapered end 36 of the bore 26. rlhis needle valve is of such length that its upper end 41 extends through the upper end of the body portion 17 into the sleeve 18. Consequently,

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a suitable stuffing-box 42 is provided for the j -a gland nut 46 threaded onto the upper end of the body 17 within 'the sleeve 18.

For convenience of manufacture, the needlev valve 3:8 is made in two portions, and the upper end 41 secured to the remainder by a suitable rivet 47 or its equivalent. lAdjaccnt the juncture of the two portions of the needle valve. aflange 48 is provided thereupon, preferably surrounding the point of'juncture. A collar 49 of outside diameter slightly smaller than the inside diameter ofthedsleeve 18, isfitted over 'theflange 48 with a shoulder 51 of the collar 49, resting upon the top of the flange 48. An upstanding annular iiange 52 is also formedv upon the collar 49, leaving an annular space 53 between itself and the sleeve 18 for the reception of a suitable thrust bearing 54.

The top lof the sleeve 18 is closed by a removable plug 56, which is threaded into the upper end thereof; and a coil spring 57 is under compression between the `plug56 and the thrust bearing 54, thus urging the collar 49 downwards Within the sleeve 18. This urging of the collar 49 downwards similarly urges the needle valve 26 downwards on account of the engagement of the shoulder 51 vof the collar upon the ange 48'o-f the needle valve, so that the action of the spring 57 is to urge the needle valve 26 onto its seat 36 to close the. fuel oil passage.

A second spring 58 is under compression between the top of the annular flangel 52 and a. shoulder 59 adjacent the upper end of the needle Valve. This spring 58 is preferably coiled about the upper end of the needle valve inside the spring 57, as clearly shown in Figs. 3, 4, and 5. j

Means for lifting the needle valve from its seat to permit'the ingress of fuel t the corn- 'bustion chamber, are provided. The form shown is the conventional rocker arm 61, operably connected to one of the moving parts of the engine such as its camshaft. and extending through' a suitable aperture in thel side of the sleeve 18 so that its bifurcated portion 62 is engaged below .the collar 49. The top of the inner face of each branch of the hifureated portion 62, is relieved to such an extent that the associated end of the rocker arm 61 may move upwards, carrying with it the coll, r 49 without engaging the -flange 48. However. the cut-away portions termiv nat-c in shoulders 63 adapted to engage the under side of the ange 48 as the rocker arm approaches the end of its stroke in the event that the needle valve becomes stuck to such an extent that the spring 58 Vdoes not raise valve may be determined by altering the position of the adjusting screw 66. in respect to the body of the injection valve.

The operation of .my improved injection valve is effected through the activation of der 59, is increased. Consequently, the needle valve 38 is raised with the collar 49, the spring 58 keeping the shoulder 48pressed 'tightly upwards against the under face of the collar 49,' unless for some reason the needle valve has become stuck, in which event the shoulders 63 will engage the under side of the collar 48 just prior to completion of the upward movement' of the associated end of the rocker arm 61. Of cou-rse, this will servle to dislodge the valve if it should be stuc It is to be understood of course, that suit able fuel is supplied under pressure through the bores 27 and 26, so that when the needle valve 38 isuthus raised, the fuel will be injected into the combustion chamber 22 through the orifices 87.

The quantity of fuel' injected at each operation of the valve is readily controllable by adjustment of the screw 66. Heretofore, it has been customary to control the lift of the valve by altering the effective length of the push rods operating the rocker arms, by meansof which the injection valves were activated. Such change in the length of the push rods however, necessarily throws out of adjustment the time at which the injection starts, as well as the time that the injection valve is closed. However, when the adjustment is effected by means of my improved mechanism without altering the length of the push rod, the timing of the opening and closing ofthe .valve is not effected.

I claim:

1. In a fuel injector, the combination with i a housing having a fuel passage communieating with an injector aperture, and a valve adapted to optionally seal or open said passage, lneans for moving said valve to open position', resilient means normally holding said valve closed, and resilient means interposed between said valve and said moving means 'within said housing.

2. In a fuel injector, the combination with a housing having a fuel passage communieating with an injector aperture, and a valve adapted to optionally seal or open said passage, means for moving said valve to open position, resilient means normall holding said valve closed, resilient means interposed between `said valve and said moving means ywithin said housing, and means for limiting the movement of said valve without effecting said moving means. j

3. In a fuel injector, the combination with a housing having a fuel passage communiw eating with an injector aperture, and a valve adapted to optionally seal 'or open said passage, means for moving said valve .to open position, resilient means normally holding said valve closed, resilient means interposed between said valve and said moving means within said housing, and means variable from the exterior of the housing for limiting the vmovement of said valve without effecting said moving means.

terposed between said valve and said moving means within said housing. j

5. In a fuel injector, the combination with a housing having a fuel passage communicating with an injector aperture, and a valve adaptedto optionally seal or open said pasj sage, means for moving saidl valve to open position, resilient means normally holding said valve closed, resilient lmea-ns interposed between said valve and said moving means within said housing, and a stop threaded through said housing in position to engage said valve and limitthe lifting 'movement thereof.

6. In a fuel injector, the combination with a housing having a fuel passage communicating through a valve seat with anr injector aperture, and a valve associated with said seat, said valve havinga stem and a shoulder thereon,acollarslidably disposed on said stem, j,

is raised, and means for raising the collar.

a spring under compression between said housing and said collar and pressing the collar onto the shoulder and the valve onto its seat, a spring under compression between YISD saidcollar and said stem to lift the valve 'from its seat when the collar is raised, yand means for raising the collar. j

7 In a fuel injector, the combination with a housing having a fuel passage communicating through a valve seat with an injector aperture, and a valve associated with said seat, said valve having astem and a shoulder thereon, a collar slidably disposed on said stem, a spring under compression between said housing and said collar and pressing the i 1 collar onto the shoulder and the val-ve onto its seat, a spring under compression between said collar and said stem to lift the valve from its seat when the collar is raised, means for wraising the collar, anjd adjustable means for limiting the movement of said valve stem.

8. In a fuel injector, the combination with a lhousing havinga fuel passage communicatment.

ing through a valve seat with an injector aperture, vand a valve associated with said seat, said valve having a stem and a shoulder thereon, a collarlslidably disposed on said stem, a spring under compression between said housing and said collar and pressing the collar onto the shoulder andthe valve onto its seat, said valve having a stem and a shoulder thereoina collarslidablj7 disposed on said stem, a spring under compression between said housing and said collar and pressing the collar onto the shoulder and the valve onto its seat, a spring under compression between said collar and aid stem to li'ft the valve from its seat when ine collar is raised, means for raising the collar, and a stop threaded through the housing in axial alignment with said valve to engage the valve and limit its lifting move- 10.' In a fuel injector, the combination with a housing having a fuel passage communicating through a valve seat withan injector aperture, `and a valve associated with said seat, said valve having a stem and a shoulder thereon, acollarslidablydisposedon said stem',

a spring under compression between rsaid housing and said collar and pressing the collar onto the shoulder and the valve onto its seat, a thrust bearing interposed between said spring and said collar, a spring under compression between said collar and said stem to lift the valve from. its seat when the collar seat, a springunder compression between said collar and said stein to lift the valve from its seat when the collar is raised, a'rocker arm adapted to periodically raise said collar, said 'rocker arm having a shoulder thereon spaced from the under side of said valve stem shoulder a distance slightly less than the total stroke of the associated portion of the rocker arm.

In-testimony whereof'I have signed my name to this specification.

` DIVIGHT E. SELBY. 

